Important Thermal Properties in Physics

Two of the most important thermal properties in physics are thermal conductivity and heat capacity. It is the reason why objects are cold on one end and eventually heat up to a certain temperature after a certain time. Notice however that some objects heat up more quickly than others. We’ll talk about how both these thermal parameters differ from each other.

What exactly is thermal conductivity?

In order for something to conduct, it has to be able to allow some “thing” to pass through it either with ease or with difficulty. Think about a block that has a bunch of little holes with it vs. a block that is hollow. If you were to run a fluid through each block, which one would allow easy passage of the water? Obviously, the hollow block would allow the fluid to pass more readily than the one with tiny holes. This same concept applies to thermal conductivity, where instead of a fluid passing through it is how much heat moves through the object. Some objects conduct heat better than others, meaning that heat can easily pass through the object. This corresponds to an object with a high thermal conductivity, while an object that has a low thermal conductivity means that heat does not easily get transferred.

What is heat capacity?

Heat capacity is exactly what it sounds like. It is how much heat an object can hold. The formal definition is the amount of heat needed to raise the temperature of an object’s unit mass or volume up by 1 unit degree. Take water and metal for example: water has a higher heat capacity than metal. This means that it takes more heat to raise a unit mass of water up by one degree than it does to raise the same unit mass of metal up by one degree. This should make sense and is why you notice how your pots and pans heat up much faster than when boiling water.

These are two of the most important thermal parameters that most scientists and engineers focus on when manufacturing a product or building something that will be subjected to high temperatures. Now, these two end up going hand in hand with each other and we will cover why that is on a later post.